Compensating drive



- Oct. 24, 1933. I A. HERZ 7 1,931,493

GOMPENSAT ING DRIVE Filed Feb. 6. 1929 Patented Oct. 24, 1933 UNITED STATES PATENT; OFFIC This invention relates to meters and more particularly to a compensating drive for volum'etric meters such as are used to measure gas fiow.,

Commercial meters for measuring commodities such as illuminating gas assess a charge depending upon the number of cubic feet of 'gas drawn through the meter. The number of cubic feet that a given amount of gas will occupy depends upon the temperature and pressure of the gas and therefor a measure which measures volume only gives rise to inaccuracies if the pressure and temperature of the gas varies to any considerable extent.

In my copending application, Serial No. 232,- 5'72, filed November 11,1927, I disclose a compensating device for gas meters which functions the drive wheel axially on the cone to increase or decrease the ratio of the meter.

lihe amount of power available on the shaft driven by the moving parts of a gas meter is rather small, and in order to satisfactorily transmit power from a smooth face cone to the drive wheel, very accurate adjustments must be maintained. The bearings of the shaft driven by the drive wheel must be properly alined to prevent binding, and the tension adjustment between the drive wheel and the cone must be maintained within very close limits if the drive wheel is to be rotated without slipping and without producing an undue drag upon the moving element of the meter.

The use of a cone of soft material having a high coefiicient of friction shortens the life of the mechanism particularly since the endwise movement of the drive wheel drags over the surface of the cone and causes it to wear rapidly. Wear must be compensated by additional tension or slippage will occur and the accuracy of the meter will be impaired. Also. materials which are most satisfactory for a drive of this kind are hygroscopic to a considerable extent and their use renders the meter susceptible to atmospheric changes. 7

In my present invention I have provided a new and improved driving arrangement for systems of this kind, an arrangement which gives a positive drive at all times without imposing ex-' cessive loads upon the moving parts of the meter.

To thisend I have replaced the smooth faced cone of my copending application with a cone containing a plurality of round bottom grooves each of'which is preferably filled with a plurality of balls, the number in each groove being in direct proportion to the length of the groove. The driving wheel is a star wheel, the teeth of which engage the balls positively even when a very moderate pressure is applied between the two. In each of the grooves I also provide a pin somewhat flexibly mounted and against which the balls bear to key themselves with respect to the cone so that they are not freeto rotate on the cone and therefore are capable of driving the star wheel.

The use of balls, such as steel ball bearings in a round bottom groove, is preferable, although a disc or washer rolling in a rectangular slot may be substituted. The ball arrangement has certain advantages however and is particularly advantageous for the ease with which the star wheel can'he moved over the surface of the balls in one row into engagement with the next row. The, halls can rotate laterally in the slot, that rotation assisting in the transfer of the star wheel from row to row.

The star wheel is mounted upon a shaft and is free to move lengthwise of that shaft within limits defined by the armsof a spider. The spider is driven by the compensating motor to adjust the ratio of the meter drive as before. The shaft carrying the driving wheel is mounted to permit limited motion radially with respect to the cone so that the driving wheel may hop or ride over the surface of the balls when the spider moves it from row to row.

In order to prevent the balls on the underside of the cone from falling out of the slot, I have incased the cone in a stationary housing against the inside surface of which the balls bear and roll 100 as the cone moves. This stationary housing is provided with a slot on the upper side of the cone which runs lengthwise of the cone, and the driving wheel engages the rows of balls through this slot.

In order to prevent the entrance of dirt into the rows of balls through this slot in the stationary housing, and to prevent the dislodgement of balls in those rows which are not in engagement with the driving wheel, I provide a rotatable cover 110 placed outside oi the stationary housing. This cover contains a spiral slot which is made to cross the slot in the stationary housing at a point directly beneath the star wheel by means of pins carried on the spider By this arrangement, when the driving wheel is centered upon one row oi balls, the rows lmmedlately adjacent on either side 01' this particular row are also exposed, through the opening deilned by the registration of the lengthwise and spiral slots. I

This opening is o! sufllcient width to expose a part or 3 or 4 of the rows on the cone. To protect these rows, I provide a small movable shutter disposed between the movable outer cover and the stationary inner housing and carried on and by the drive wheel bushing. This small cover has a hole in it Just large enough to permit engagement of the star wheel with one row of balls, so that the unused rows are overed at all times.

By this arrang ment, I have provided a new and improved compensated drive for meters oi this class, an arrangement which is positive in its action, reliable over wide variations in temperatures and atmospheric conditions, and inexpensive to install and maintain.

' The details of my invention can best be understood with rcterenceto the accompanying drawing, in which I have illustrated a preterred iorm of the invention to enable one skilled in the art to acquire an understanding of it, and in which:

Figure 1 is a diagrammatic view oi my invention applied to a gas meter;

Figure 2 is a sectional detailed view Figure 1 taken along the line 2--!t, looking in the direction of the arrows;

Figure 3 is a fragmentary detailed plan view of Figure 2, looking downward;

Figure 4 is a detailed view oi a portion of the cone; and

Figure 5 is a detailed sectional view of Figure 3, taken along the line 5-5 and. looking in the (ii-- rection of the arrows.

Referring to Figure t more in. detail, the one meter is shown diagrammatically at i. The par tlcular type 0! gas meter employed'is of course immaterial, so long as it provides means for rototing the shaft (at a speed proportional to the cubic feet of gas drawn through the meter.

The compensating device comprising the cone 5, and drive wheel 6. is attached to anddriven by this shaft 4. The particular method of attaching the meter may be varied greatly within the teaching of my invention.

The compensating mechanism, which is disclosed in full in my copending application hereinbei'ore mentioned is not oi the essence of the 'present invention, and reference is hereby made to my copending application for a detailed explanation of its operation.

Briefly the compensating mechanism comprises the pressure element 15. connected to the outlet pipe of the meter, and acting upon the pressure element 16 which is connected to the manometer tube 17. Within this tube is a mercury column. maintained in engagement with contacts 18 which are carried. by arbor 19 upon the screw thread 12. Contacts 18 control the motor 7 and the relay 20, normally maintaining relay iii) energized when the compensating means is set correctly. A lowering oi the pressure or the gas flowing through the meter lowers the level of the mercury column and moves it out of engagement with the contacts 18 to deenergize the relay 20.

The deenergization ot the relay 20 01cm the in one direction or the other to move the ill umn.

movement produced by the thermal ciemen circuit of motor l screw ii, thereby altering; t. spider and the drive wheel. i? w cone, and to rotate the screw shai iii inn gears 10 and 11 to lower the bushing iii and contacts 18 so that the contacts 18 again dip the mercury and close the circuit oi! relay til.

The temperature compensation tlt'lmlili'liwt thermal element 14 which operates against t bell crank 13 to raise the screw shaft iii to mi the contacts 18 out of engagement with the cury, or to move it downward to engage i 1 second one of the contacts 18 with the min" The motor is thus energized over a circuit trolled either through the baclr contact o1. 20 or through the second contact 18, and rota wheel ii with respect to the cone t3 and to road" the contacts 18 with respect to the mercury c The gearing driven by the motor "l to drive the arbor 19 to raise or lower the contacts iii with respect to the level of the mercury in i tube l'i, comprises a follow up device wi causes the contacts to follow the movement ,i duced by the pressure element id, or reverse In the present invention the star wh. mounted upon the square shaft 11. which is nected to the registering mechanism of the not. through a flexible coupling 3. This register mechanism is of the usual type employed fo meters, and registers the number oi cub passing through the meter. The shaft 3 ported by the levers 41 which are pivo" bosses 40 disposed on opposite ends oi the con These bosses may either be attached to t 'tionary housing surroundiniithc cone, or he extensions of the frame member to.

The levers ii are pulled down icy springs 42, best seen in Figure ii, to a mi proper tension between the drive wl the balls .iii on the cone. This pivo levers 4i permits limited movement o wheel radially with respect thereby enable the drive wheel to ride up the surface oi the balls when it is heh'ltj; mm t irom one row to anoiiiicr.

From Figure 5 it will. be seen that th or thickness of the star wheel 8 is exam to the distance between centers of adj scent rows. That is, the thickness o wheel equals the diameter of a ball plus tance between the rows. The necieesit dimension will be brought out hereinw ther, the teeth oi! the star wheel are hoilowe that when the wheel is riding squarely c1311 0! balls, the concavity oi the teeth con ity of the ball keep the wheel in alignment wi the row and. a large surface is presented for transmission of power from ball to wheel. Wh the wheel gets out of alignment, as it will when it is being moved from one row to the next, the bearing of the wheel on the balls is along a line rather than a broad surface, that is bearing is a knife edge bearlne'. A knite hear 14:. ing on a sphere is unstable, thus causing the wheelto move in jumps from row to row and to quickly realign itself with the new row.

v The cone 5 contains as many grooves as there are rows of balls in the device, and contains one slot 35, best seen in Figure 4, running iongitudinally oi. the cone. This slot is rectangular in shape and deeper than the grooves on the cone.

Within this slot is a comb comprising the base 3% to which the pins 32 are attached by the iiexible mounting member 33. The member 33 is preferably a small spring through the movement of which the assembly may be flexed in all directions within the limits of the space in the grooves in which the pin 32 is located. The number of pins 32 corresponds with the number of grooves 30 in the surface of the cone. These pins serve to lock the balls in the groove to prevent their rotation around the cone.

The cone 5 is mounted upon the shaft 4 of the meter, and incased in the stationary sheet metal housing 44, which is preferably attached to the frame member 23, and which completely incases the cone. The housing 44 is provided with a lengthwise slot 45 disposed on the upper face of the cone and running parallel to the shaft 4. The

star wheel 6 projects through this slot 45 to engage the balls on the cone. The housing 44 is spaced away from the surface of the cone sufficiently to permit the balls 31 to ride freely around the cone by bearing against the inner face of the housing 44 when on the lower side of the .CODE.

Around the housing 44 is a movable sheet metal cover 43 which is provided with a spiral slot 46 into which the pins 48, carried by'the spider 9 and best seen in Figs. 3 and 5, are projected to rotate the cover 43 when the spider is moved by the motor. The ends of the cover 43 are turned over to form the round cylinder-like end 43', which bears against the frame 23, or against a projection of the housing 44, to prevent a lengthwise dislodgement of the cover.

Theregistration of the spiral slot 46 and the longitudinal slot 45 leaves an open space through which the balls on the cone are exposed.

This opening is in the shape of a parallelogram, and exposes part of 4 or 5 of the rows only'one of which is engaged by the star wheel 6. To protect the rows of balls so exposed, I attach a small rectangular shutter 4'1 to the bushing carried by the star wheel 6. This shutter 47 closes that portion of the opening not needed by the star wheel 6, moves with the star wheel lengthwise inv the slot 45, and is disposed between the stationary housing 44 andthe movable cover 43.

When the star wheel is engaging a row of balls at the extreme end of the cone, the shutter extends beyond the housing 44 for a short distance. To permit this extension that portion of the rolled edge 43' of the cover 43 which is adjacent to the end of the spiral slot 46 and is then aligned with the slot 45, is cut away, and a slot 23, Fig. 5, is cut in the frame member 23.

The shutter 47 is made of a light sheet metal preferably aluminum, so that it will not effect an appreciable drag on the star wheel 6 when that wheel is moving it. The rolled edge 43' of the cover spaces it away from the housing, and since the roll 43 is larger than the thickness of 47, the latter slides freely under the control of the star wheel. If desired, a keyway or slot 48' the groove 30 and around the housing 44. The

balls 31 do not completely fill the space in the groove, that is, the circumference of a circle passed through the diameters of the balls is slightly greater than the sum of the diameters of the individual balls, so that there is a small amount of play between the balls. The teeth on the drive wheel 6 ride in this space between the balls and over the outer surface of a ball with an engagement simulating that of gear teeth, so that the wheel 6 is positively turned by the movement of the cone 5. The end of the pin 32 is of the same diameter as a ball, and of similar shape, and the star wheel 6 rides over it in the same manner.

The width of the star wheel 6 is exactly equal to the distance between the center of adjacent rows of balls, as seen in Fig. 5, that is, it is equal to the diameter of the ball'plus the distance between adjacent rows. The wheel 6' is loosely mounted within the spider 9. and capable of limited lengthwise motion within that spider to thereby insure that the wheel will ride squarely up on one of the row of balls.

When the motor 7 is actuated by the compensating device to move the spider arm, the wheel 6 is notimmediately moved but rather the arm 9 moves over into engagement with the-bushing carried by the wheel 6. As the arm 9 continues to move, the wheel 6 is raised up over the surface of theballs, in adjacent rows, the shaft 3 moving outward-against the tension of spring 42 and moving with respect to the spider 9 in the slot 9'.

When the wheel 6 has reached a position shown in Fig. 5 with its edges centered squarely upon the balls in adjacent rows, the tension of spring 42 pulls it down rapidly, the edges of the wheels sliding over the surface'of the ball to move the wheel and bushing with respect to the. spider 9.

The cover 47.is moved by the bushing of the wheel 6, to thereby insure that the row of balls from which the wheel has departed is completely covered to prevent any of -the balls in thatrow from jumping out of the slot. If the spider -continues moving in the same direction, the

wheel 6 gradually rides 'up overthe next two balls in adjacent rows, and again jumps ahead when its edges have passed the center of the balls.

By this arrangement, the gear ratio between the meter and the regis r is changed in correspondence with the diffe ent numbers of balls in adjacent rows on the cone surface. It is true that some slight variation is encountered when the wheel 8 moves from one row to another, that is, some motion is lost or gained, but this introduces so small an error as to be of no conse-- quence, particularly since it is a transient error and does accumulate with time.

As the spider 9 moves forward, the pins 48 bear against the edge of the slot 46 to rotate the outer cover 43 in a direction corresponding to the motion of the spider. This covers the rows of ballsbehind the star wheel, and uncovers those ahead of the star wheel, to give the star wheel access to the rows with which it is breught into engagement by the spider movement.

The gear-like action exercised upon the star wheel by the walls in a row affords a positive drive, and does not require a great amount of tension between the star wheel and the balls since the amount of power to be transmitted is slight. The drive of the register mechanism is thereby made positive, without subjecting the meter to a -heavy load such as would be required if friction alone wererelied upon to drive the register. The amount of compensation depends upon the differenoe in diameters between the smell and large ends the cone and the consequent diii'erenee in the number of balls rooting in each of the slots to another to alter ried by said Moi" W on the cone. Inasmuch as the pressure and temperature variations encountered in a gas syotem are relatively small, a wide variance in the gear ratio is not required, and a minimum or 1-1 gear ratio and a maximum of l -l has been found to be satisfactory.

Since there are diflerent number of hello in each of the rows on the oone, the star wheel will not ride squarely between adjacent balls in :9. row lift it is being moved from one row to another, hut rather will often times strike squarely upon the top of a ball.

A slight movement of the cone 5 will dislodge the star wheel from the top of the bail and amine it to pro] t its teeth l ween adjacent hells the row, however, but s alight rotation will lost or gained toy such ooeration, Then too, halls in the row are not ghtiy fixed with n to each other, and some motion is lost with revolution oi the cone. However, both oi l errors are very slight, and no difiloulty he experienced in maintaining a gas meter as, within the required one percent with the arm menta shown in the drawing.

While 1,, have chosen to thow my invention in. connection with a preierred embodiment oi. "l have done so by way oi. the example only; there are modifiootlons and odop no which can he made by one skilled in the art w? out department ifrom the teochinge of the lotion tion.

Having thus compiled with the etotutoo owl hown and desoribed o preferred form of ention, what I oonsider ow and, desire t protected ov Letters Patent is Winbfllll wt in, in pended claims.

1. in a. device of the mo e t'lesoribolii, o driven oone, said cone having a volnrolity 0! gm posed parallel to its base, a plurality oi ho. hosed in said grooves, moons tor locking th ollo against rotation around, the cone in said grooves,

- means tor holding the balls in the grooves,

,wpider, a star wheel carried thereby, means for holding said star wheel in engagement with the balls in one of said grooves, a shaft driven through said none and stnr wheel at a, rate dependent upon the ratio ailiorded lay the cone and star wheel, and means for moving said spider to alter said ratio,

2. In a devioo ot the claw described, a rotatable cone having at plurality oi grooves disposed paw allel to its base, it "row oi bolls: disposed in each groove, means for lilCRlli hells against rotaw tion around the cone in sold mwiloves, a housing around said cone and hello and having a longitudinally disposed slot, not l around said housing and having a spiral olot registering with said longitudinal slot to expcoe a portion oi! said rowe 0! balls, a star "wheel, a shutter having an opening registering with sold. slots to expose one of said rows, said stair whee ovtemling through said opening into driving orient with the balls of said exposed row, meme; for moving; said cover to cover some of the rows oi hulls exposed through said slots and to one other rows, said means also moving sold std wheel lrom one row 0! balls liming ratio, means carfor moving said shutter row of hulls "with which the means for holding the with the balls.

of tho close described to expose o i tho star wheel is or a star wheel in e o 3. A meter driven in M comprising a. driven oono provided with a pillrallty of grooves which in. planes normal to the axis of the cone, none oloo Toning provided with a, slot running lengthwise of sold none, pins, means for flexibly nriounting the in. lllld slot and registering" with told grooves, there a pin for each of mid gi'mwes, o :r-row of halls in each groove, means for :1 "ring told hello in said grooves, a register during otor wheel hold in engagement with and driven by the pin and balls of one 0! said rows, horizons for moving said star wheel Irom one row to another." to alter the ratio of movement of oniv wheel. with reopect to the movement of told no, oocl meant for holding the star wheel o :ogemoht with the halls.

4. In a meter driven w scribed, a. shaft, o. shaft, the mcmniinr, wheel lengthwise o rotation of one with 1 sold oone having grot pianos normal to ,1, hells mounted l and disposed adiooent rows is engaged lzmr taining the hello m. t ing the balls revo 1o none, means for in vi row over the on, ment with the n ohaft yielding to i. when. saidwheei ii. in a tremor plurality of mm to mid rows of hallo i r normal to o connnon or the supporting :menm for said hello ohoot solid oupportino memo, it Still said. rows, o oho'it support 1o oioso lieon oppooite oi having openings through tends, means for moving" wheel along said short, the tops oi. oaid bollo r halls being moved to mill and means Ior retaining the ing means.

6. In a. transmission-o plurality of evenly spool a difierent numher of Lior supportinui, ooid row: the balls inv the rowo movement along the row, i conforming to the show; o having a thickness ooool tween the centers of orljom of balls, means for holding: ment with said balls including for movement relative tomoving at a uniform rate a: o spider for moving said i said rows, the m xes of st suriaee oi the balls in high spot 01 the ball is stepping away .from a to. the Wheel edges slide dowi of the ball to bring the wl with the next row, to the o! revolutions made by mi oi the support.

1,931,493 '7. A variable drive between a meter and a register, comprising a cone frustrum member having a plurality of grooves disposed on its surface in planes perpendicular to the axis of, the cone, a row of balls disposed in each of said grooves, means for limiting the movement of said balls longitudinally of said grooves, means for holding said balls in said grooves, a star wheel member, means for holding said star wheel member in engagement with said balls, said balls driving said star wheel, means for moving said star wheel member from row to row to thereby alter the ratio of rotation of said star wheel member to that of said cone member. g

8. In a transmission of the class described, a

- right cone frustrum having a plurality of grooves disposed on said cone parallel to its base, a row of balls disposed in each of said grooves, means for retaining the balls in the grooves, means for limiting the movement of said balls longitudinally of said grooves, a stationary housing surrounding said cone and spaced away therefrom to form a 'guide against which said balls rest, said housing cone having a plurality of grooves in its surface and parallel to its base, pins flexibly mounted, one in each groove, a plurality of balls disposed in each groove, said balls being free to rotate about their centers in the grooves and restrained by said pins from rolling lengthwise around the grooves, means for holding the balls in the grooves, a rotatable star wheel engaging said balls one row at a time, means for holding said wheel in engagement with said balls, and means for moving said star wheel onto the crest of a ball in one row from which crest the rotation of said ball assists said means in stepping the wheel to the adjacent row.

10. In a compensating drive for meters, a meter driven cone having a plurality of grooves in its surface parallel to its base, pins, means for flexibly mounting a pin-in each of said grooves, a.

plurality of balls disposed in each of said grooves, said balls being free to rotate about their centers in the grooves and restrained by said pins disposed in which opening said wheel may make limited movement responsive to a rotation of said balls to center the wheel on a row of balls, and means for moving said spider to move said star wheel onto the crest of the balls of that row from which crest the rotation of said ball assists said spider in stepping the wheel to the adjacent row. a

11. In a device of the class described, a cone having a plurality of grooves in its conical surface and in planes normal to its axis, pins, means for flexibly mounting a pin in each of said grooves, a plurality of circular bodies disposed in each groove, means for holding said bodies in said grooves, said bodies being restrained by said pins from rolling lengthwise around said grooves, a star wheel engaging the bodies in one of said grooves, means, for holding said wheel in engagement with said bodies, and means for moving said star wheel from one groove to the next.-

12. In a compensating drive for meters, a meter driven cone, a plurality of evenly spaced rows of circular bodies on said cone, there being a difierent number of circular bodies in each row, a pin flexibly disposed in .each of said rows, a register driving wheel having teeth conforming to the shape of said bodies, said wheel having a thickness equal to the distance between centers of adjacent ones of said rows of bodies, meansrfor moving said wheel from row to row to thereby change the number of revolutions made by said wheel for revolution of the cone, means for holding said wheel in engagement with said bodies, means on said cone for receiving said bodies, and means for preventing movement of said bodies longitudinally thereof, and means for retaining the bodies on the cone.

13. In a device of the class described, a shaft, a star wheel mounted on said shaft, said mounting permitting lengthwise movement of said wheel on said shaft and preventing rotation of one with respect to the other, a cone, rows of circular bodies on said cone adjacent to said wheel, one of said rows being engaged by said wheel, a pin flexibly disposed in each ofsaid rows, means for moving said wheel from one row to another, a mounting for said shaft which yields f to outward movement when said wheel rides over one of said bodies as it is moved from row to row, means on said cone and extending in a plane normal to the axis of the cone forreceiving the bodies in rows, means retaining said bodies on the cone, and means for preventingmovement of said bodies longitudinally of said receiving means.

- AIJ'RED HERZ. 

